1. Field of the Invention
The present invention relates to a robot system capable of performing regulated movements, and more particularly, to various types of robot systems which operate within the same activity space as that of a human.
2. Description of the Related Art
In a related-art robot system, a mechanism system having a skeletal frame made of metal or resin is actuated by means of motors, actuators, or engines, which employ various types of power. A required posture of a robot system is maintained through several steps. First, information obtained by way of various internal and external sensors is processed through use of a controller. Here, the controller is mounted on a robot system main unit or outside the main unit and can exchange information with the robot system main unit. Next, restoration force stemming from gravity is utilized by use of a balance controller which issues required instructions to individual drive sections and shifts a corresponding weight, or by loading into a bottom ballast corresponding to a weight sufficient for canceling out a shift of center of gravity in the upper potion. By virtue of these operations, the system requires complex information processing. Further, the robot system is heavy and rigid and poses danger to a human when operated within the same activity space.
In order to prevent such a danger, the robot system must be made slim and slender. However, realization of a slender robot system is difficult in terms of preservation of shape of a structural body. Robot systems, including a walking robot, require integration and appropriate control of a large number of sensor and drive systems for effecting preservation of system posture, stable self-support, and movements. Therefore, a heavy load is imposed on an information processing system, in turn rendering the information processing system bulky and involving consumption of massive amounts of energy. Further, restrictions are imposed on the weight of the overall robot system. Particularly, considerable influence is imposed on a self-supporting system or autonomous system. When restoration force for effecting an attitude control is dependent on a restoration moment stemming from gravity, a robot system is equipped with ballast, thereby rendering the total weight of the robot system heavy.
An object of the present invention is to provide a robot system which does not requires a complex attitude control system or heavy ballast and maintains a stable posture regardless of whether the robot system is stationary or operating.
In order to accomplish the object, according to the present invention, there is provided a robot system comprising:
at least two segments;
joints for interconnecting the segments;
drive units for actuating the segments;
a controller for controlling the drive units; and
a bladder which is provided in at least one of the segments, the joints, the drive units, and the controller and which is filled with a fluid, the fluid being of higher specific gravity than the outside environment.
The robot system possesses a center of buoyancy and a center of gravity which differ from each other. Further, the robot system has a specific gravity of 1 or more relative to the outside environment.
In the robot system, the product of gravitational force and a distance between a ground point (where the system comes into contact with the ground) and the center of gravity is smaller than the product of buoyant force and a distance between the ground point and the center of buoyancy.
In the robot system, the bladder is formed in the segments. The robot system is equipped with a regulator for regulating the amount of fluid filled in the bladder.
The robot system is equipped with a valve for filling the bladder with a fluid or releasing the fluid from the bladder. The valve may be a check valve for preventing outflow of the fluid from the inside of the bladder to the outside.
According to an variation of the present invention, the robot system may be constructed such that one of the segments constitutes a leg section. Buoyant force may be greater than gravitational force so that the leg section can contact a ceiling. Moreover, the robot system may be constructed such that the leg section comes into contact with a water surface.
In the present robot system, the bladder is preferably formed from a flexible material, and the fluid pressure exerted on the inside of the bladder is preferably variable.
The robot system may be equipped with a transceiver for transmitting information to the outside and receiving information from the outside and may be constructed so as to remotely control the drive units.
The robot system is equipped with a power supply unit for supplying energy for driving the drive units.
The robot system has sensors for acquiring information about the inside and outside of the robot system.
Moreover, according to the present invention, there is provided a robot system comprising:
bladders, each having one or more skins and being filled with a fluid having specific gravity higher than that of the outside environment;
a joint structure capable of linking the bladders together;
a drive unit for actuating a bladder or mutually actuating the bladders; and
an information processing device for controlling the entire system, wherein
the overall robot system has a specific gravity of one or more relative to the outside environment under normal circumstances; the robot system is self-supported while touching a floor at one or several arbitrary points; and the robot system can move as a system.
According to the present invention, the robot system is suspended by means of buoyant force developing in the bladder filled with a fluid having specific gravity lower than that of the outside environment. In the event of occurrence of changes in the posture of the robot system due to movement of the robot system, disturbance, or other forces, a vibration system is formed while an arbitrary ground point on the floor or the center of gravity of the robot system is taken as a neutral point. By means of restoration force stemming from buoyancy, the overall robot system is maintained in a stable attitude.
Simultaneously, the skin of the bladder is strained by the fluid filled therein, thereby generating tensile force. The tensile force imparts required strength, rigidity, and flexibility to respective segments, thereby enabling preservation of the shape of the structural body, self-support, and movements such as walking or leaping action. Further, the segments"" flexibility enables absorption of impact force.
The present invention forms a stable system in the form of a lightweight, simple robot system through use of restoration force without dependence on gravity. As a result, load imposed on the information processing system is lessened considerably. Of various functions of a skeletal system, the most fundamental role of the skeletal system as a support mechanism is greatly diminished, thereby significantly reducing the weight of the skeletal system. As a result, the weight of the robot system main unit is reduced. Further, there can be provided a robot system which possesses structural strength sufficient for effecting self-support action and movements, is suitable for use in the same environment as that in which humans are present, and does not pose any danger to humans even when the robot system falls to the ground or hits any humans.